They are as happy as can be for being grown so big in a small pot.
Your are right, i was also surprised with the vigor and stretching of this mostly indica cross when we tested it for the first time, i like to describe it like a big indica with slight sativa influence. Its strong branching, moderate node length and leaf shape are quite desirable to allow correct light penetration indoors and to provide good yields.
Wish they enjoy the flowering in your balcony. Best wishes!